Germ cell tumors

Overview

Germ cell tumors are growths of cells that form from reproductive cells called germ cells. In the female reproductive system, germ cells turn into eggs. In the male reproductive system, they turn into sperm. Most germ cell tumors happen in the testicles or the ovaries.

Some germ cell tumors happen in other areas of the body, but they are very rare. These are called extragonadal germ cell tumors. Examples of where these tumors can form include the belly, brain and chest. It's not clear why germ cell tumors form in places other than the testicles and ovaries.

Some germ cell tumors may be cancer, but others are not cancer.

Treatment for germ cell tumors may include surgery, chemotherapy and radiation therapy.

Symptoms

Symptoms of germ cell tumors depend on where they happen. Symptoms often happen because a growing tumor puts pressure on nearby tissue or organs. For example, a germ cell tumor in an ovary may lead to pelvic pain, back pain, bloating or swelling in the belly. A germ cell tumor in a testicle may cause swelling or pain in the testicle or scrotum. A lump in the testicle is a common symptom of a testicular germ cell tumor.

Causes

It's not clear what causes germ cell tumors. Germ cell tumors form in the cells that turn into eggs in the ovaries and into sperm in the testicles. Germ cell tumors happen when germ cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA tells the cells to grow and multiply at a set rate. The DNA also tells the cells to die at a set time.

In tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to grow and multiply quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. The tumor cells can form a mass that can grow and press on nearby tissue or organs.

Sometimes the DNA changes turn germ cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. Cancer cells sometimes break away and spread to other parts of the body.

Risk factors

Factors that may raise the risk of germ cell tumors include:

• Young age. Germ cell tumors tend to happen at a young age. For example, germ cell tumors that form in the ovaries are more common before age 20. Germ cell tumors that form in the testicles are most common between the ages of 15 and 35.
• Undescended testicle. Having a testicle that doesn't move down into its proper place in the scrotum before birth may raise the risk of a germ cell tumor in that testicle. The medical term for this condition is cryptorchidism.

Healthcare professionals haven't found anything that can prevent germ cell tumors.